How to Fix RV Slide Out Leak with Quick Power Gear Rail Timing Adjustment

What do you do when your slide out leaks and you’re not sure why? Unless you want to spend a lot of time and money at some RV shop, the answer is to first find out the cause of the leak, then fix it yourself!

Why Does My Slide Out Seal Leak?

The most challenging part of any RV maintenance project is often determining the exact cause of the problem, and identifying the proper terminology regarding any applicable fix. The fine folks at Northwood Manufacturing have always been very helpful whenever I have called to inquire about the equipment and appliances in our Arctic Fox 275B or previous AF 245N.

When troubleshooting a leak along one wall of the slide in our fifth wheel, I discovered the top flap seal was not creating a tight seam along the roof. A gap of nearly 1″ was allowing rainwater to penetrate the inner seal and run down the wall inside our RV.

OK, step one accomplished. But why wasn’t the flap sealing properly? Inside the RV, I ran my hand behind the interior seal with the slide all the way out, and discovered a gap behind the trim on one side of the room. I suspected the slide was out of alignment, so I took a closer look at the mechanism that moves the room under the rig. Upon initial inspection, I discovered the slide-out rails and motor assembly are really pretty simple—a drive motor, shaft with gears at both ends, and two rails.

I measured the distance on each side of the slide to confirm my suspicion. One side was extended out nearly 2″ farther than the other. I thought there’s gotta be a simple way to realign the slide. There is.

Synchronize Your RV Slide-Out Rail Timing

The technical term for describing our slide being out of alignment is: the rails are out of synch, or the gear timing is off. So, technically speaking I adjusted the timing of the rails supporting our slideout to realign the room. Follow these simple steps below to synchronize your RV slideout rails, and adjust the slide to prevent leaks caused by a misaligned flap seal.

Note: These instructions are for synchronizing a two rail slide-out room with the Power Gear slide-out system for standard or flat floor. Procedures for your system may vary
RV Slide-Out Adjustment

Image courtesy of Power Gear, click to enlarge.

Power Gear Slide-Out Inner Rail Alignment

  1. Remove cotter pin from idler drive shaft.
  2. Push the idler drive shaft toward opposite rail to disengage the gear from the gear rack.
  3. Adjust the gear timing by sliding the idler rail side of the room to the proper position (Measure to ensure the same distance from
    the frame as the drive rail side).*
  4. Push the idler drive shaft back into position, engaging the gear onto the gear rack.
  5. Reinstall cotter pin into idler drive shaft.

Extend and retract the slide a few times and check for proper room flange sealing. If the room is not properly aligned, repeat steps 1 thru 6.

*Depending on the size of your slide, you may need help moving the room by hand.

Tip: To move idler rail once the gear is disengaged, lift the room from the outside or push that side of the room out from the inside.

Download Power Gear Slide-Out System Manuals

Photos of DIY Slide-Out Rail Alignment

Since a picture’s worth so many words, below are some photos I took to help illustrate the steps described above for synchronizing our Power Gear RV slide-out rails.

RV Slideout Rails Timing Gear Adjustment

Idler rail with gear in functioning position.

The photo above shows the idler rail, or “slave” rail with gear engaged in the normal operating position and cotter pin attached. It is not necessary to remove the drive shaft from the gear (retainer bolt shown at left).

RV Slideout Rails Timing Gear Adjustment

Idler rail with cotter pin removed and gear disengaged from rack.

By removing the cotter pin, the gear can easily be disengaged from the idler rail gear rack by sliding the drive shaft toward the drive rail, under the opposite side of the room (to the left in this picture).

The gear disengaged easily for me by shaking the drive shaft a bit as I shoved it toward the other rail. The nut shown at right is the manual override nut for manually moving the slide in the event of motor failure. Tap on that lightly with a mallet while sliding the drive shaft if necessary.

RV Slideout Rail Gear Timing Adjustment

Disengaged slide-out rail gear.

Once the idler rail gear is off the rack, both rails can be synchronized by manually moving the disengaged side until the room is aligned properly. Refer to photo above of gear engaged on the rack in proper functioning position before operating slide-out.

How to fix RV slideout seal leak

Once the gear is engaged, operate the slide-out and measure the depth of the slide on both sides to ensure proper alignment. Measure under the slide from the frame to the inner wall and/or from the exterior of the RV to the outer edge of the slide.

Finally, visibly inspect the flap seal to ensure a tight flange seam. Compare these two photos to the very first pictures in this post above and notice how synchronizing the slide-out rail gears fixed the gap causing water to leak into our RV.

I guess we won’t know if this fix did the job until the next big rain storm, but the seam sure looks a lot better! Subscribe below to be notified of future blog updates if you want to find out.

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6 Responses to “How to Fix RV Slide Out Leak with Quick Power Gear Rail Timing Adjustment”

  1. I have a slide that is only leaking on one corner. I thought maybe the slides were out of alignment like you talked about above but they measure the same distance at the bottom. The actual slide itself is a couple inches short of fully extending on one top corner. I have inspected the top of the slide and there is nothing keeping it from extending out. This camper has 2 slides and everything seems to measure up to it other than one top corner. Any suggestions?

    • they measure the same distance at the bottom. The actual slide itself is a couple inches short of fully extending on one top corner.

      Sounds like the vertical alignment is off. See my link above for the slide-out room vertical adjustment instructions.

      Good luck!

  2. Jim, Great web site. I found your site when looking for adjusting the Power Guide slide. Great instructions. Thanks.
    You have a great deal of information on your site…many of your upgrades I’ve been considering. It’s great to get first hand experience.

    I look forward to reviewing your site.

  3. i have a 30ft 1 slide-out…when i take it in, the top hits first then the bottom comes in and when it is all in my slide floor is up off the trailer floor by a couple in. …when out it seems to be level ….the sides are equal coming in or going out ..what do i adjust so my slide seals evenly when put in ? thank you for your time and knowledge

    • Our slide will also raise the floor a bit when fully closed, but not by a couple inches. Review the manual for your slide and you should find the mounting bolts at the end of the rails, near the exterior wall of the slide. The mounting plate should have some slotted holes that will allow you to raise or lower the outer end of the slideout. Just be careful, as raising it too much could cause a gap under seal when fully extended. Good luck Dale!

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